Spatial and temporal impact of fungicide spray strategies on fungicide sensitivity of <Emphasis Type="Italic">Mycosphaerella graminicola</Emphasis> in winter wheat

Field experiments, involving various fungicide strategies with pyraclostrobin and/or epoxiconazole were carried out in 2004 and 2005, with the overall purpose of monitoring the evolution of fungicide sensitivity in Mycosphaerella graminicola on different isolates per leaf, leaf levels at different points of time, and points in the field. Sensitivity was assessed on single isolates by means of epoxiconazole EC₅₀-values, and monitoring of the G143A-mutation, which confers strobilurin resistance. In both years, fungicide application strategies did not cause any significant shifts in epoxiconazole sensitivity of the population median or variance over time compared to the starting population. In 2004, the end-population median was the same for all sprayed strategies, although compared to untreated median sensitivities were higher. In 2005, epoxiconazole sensitivity levels were similar on individual flag leaves and different points in the field. Measured on all isolates the EC₅₀-values ranged from 0.007–1.15 mg l⁻¹. In 2004, due to the high initial level of pyraclostrobin resistance, stabilisation of pyraclostrobin resistance was observed following the various combination treatments. No correlation between epoxiconazole sensitivities and pyraclostrobin resistance were observed. High input strategies using a mixture of epoxiconazole and pyraclostrobin resulted in the best control and yield response. A subpopulation of the isolates from 2004 was also screened for sensitivity towards five different triazoles of which tebuconazole proved to be least sensitive, and this could further be split into two subpopulations.     

The 1949 Atlas of French peat deposits,a starting point for a national inventory of peatlands

Fifty per cent of European peatlands are in a damaged state. While intact peatlands are natural carbon sinks, degraded sites release important amounts of greenhouse gases into the atmosphere, contributing to global warming. Restoration of the hydrological functionality of peatlands has proved to be an efficient tool to avoid these emissions. In France, Tuffnell & Bignon's ministerial report (2019) emphasized the need for peatlands ‘integration into the National Low Carbon Strategy, targeting carbon neutrality by 2050. However, current knowledge regarding French peatlands’ distribution and carbon stocks is insufficient and does not allow decision makers and managers to prioritize areas for restoration. The most complete database to date is the 1949 Atlas, an inventory of exploitable peat deposits that was conducted during WWII for peat exploitation as fuel. Until its digitalization, the latter database was archived and never used in a scientific study. It provides detailed information about peatland surfaces, peat thicknesses and carbon contents at that time. We estimated peat carbon stocks from French peatlands to be 111 Mt C in 1949 for 63,290 ha identified as peaty sites, the equivalent of 3% of the organic carbon contained in the upper 30 centimetres of French soils. 34% of this stock was held in Lower Normandy (37.7 Mt C) and 12% in the Picardy's region (13.0 Mt C), in large lowland peatlands. However, not all peatlands were prospected in the 1949 inventory and the characteristics of the prospected peatlands may have changed with anthropic disturbances of the last decades, such as draining or climate change. These first results highlight the need for a recent inventory of French peatlands and carbon stocks based on local data aggregation. Data from the 1949 Atlas could help constituting this new inventory but should be validated before being used to describe the present.